Amyotrophic lateral sclerosis (ALS)
Amyotrophic lateral sclerosis (a-my-o-TROE-fik LAT-ur-ul skluh-ROE-sis), or ALS, is a progressive nervous system disease that affects nerve cells in the brain and spinal cord, causing loss of muscle control.
ALS is often called Lou Gehrig's disease, after the baseball player who was diagnosed with it. Doctors usually don't know why ALS occurs. Some cases are inherited.
ALS often begins with muscle twitching and weakness in a limb, or slurred speech. Eventually, ALS affects control of the muscles needed to move, speak, eat and breathe. There is no cure for this fatal disease.
Signs and symptoms of ALS vary greatly from person to person, depending on which neurons are affected. Signs and symptoms might include:
- Difficulty walking or doing normal daily activities
- Tripping and falling
- Weakness in your leg, feet or ankles
- Hand weakness or clumsiness
- Slurred speech or trouble swallowing
- Muscle cramps and twitching in your arms, shoulders and tongue
- Inappropriate crying, laughing or yawning
- Cognitive and behavioral changes
- ALS often starts in the hands, feet or limbs, and then spreads to other parts of your body. As the disease advances and nerve cells are destroyed, your muscles get weaker. This eventually affects chewing, swallowing, speaking and breathing. There's generally no pain in the early stages of ALS, and pain is uncommon in the later stages. ALS doesn't usually affect your bladder control or your senses.
ALS affects the nerve cells that control voluntary muscle movements such as walking and talking (motor neurons). ALS causes the motor neurons to gradually deteriorate, and then die. Motor neurons extend from the brain to the spinal cord to muscles throughout the body. When motor neurons are damaged, they stop sending messages to the muscles, so the muscles can't function.
ALS is inherited in 5% to 10% of people. For the rest, the cause isn't known.
Researchers continue to study possible causes of ALS. Most theories center on a complex interaction between genetic and environmental factors.
Established risk factors for ALS include:
- Heredity. Five to 10 percent of the people with ALS inherited it (familial ALS). In most people with familial ALS, their children have a 50-50 chance of developing the disease.
- Age. ALS risk increases with age, and is most common between the ages of 40 and the mid-60s.
- Sex. Before the age of 65, slightly more men than women develop ALS. This sex difference disappears after age 70.
- Genetics. Some studies examining the entire human genome found many similarities in the genetic variations of people with familial ALS and some people with noninherited ALS. These genetic variations might make people more susceptible to ALS.
- Environmental factors, such as the following, might trigger ALS.
- Smoking. Smoking is the only likely environmental risk factor for ALS. The risk seems to be greatest for women, particularly after menopause.
- Environmental toxin exposure. Some evidence suggests that exposure to lead or other substances in the workplace or at home might be linked to ALS. Much study has been done, but no single agent or chemical has been consistently associated with ALS.
As the disease progresses, ALS causes complications, such as:
Over time, ALS paralyzes the muscles you use to breathe. You might need a device to help you breathe at night, similar to what someone with sleep apnea might wear. For example, you may be given continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) to assist with your breathing at night.
Most people with ALS develop trouble speaking. This usually starts as occasional, mild slurring of words, but becomes more severe. Speech eventually becomes difficult for others to understand, and people with ALS often rely on other communication technologies to communicate.
People with ALS can develop malnutrition and dehydration from damage to the muscles that control swallowing. They are also at higher risk of getting food, liquids or saliva into the lungs, which can cause pneumonia. A feeding tube can reduce these risks and ensure proper hydration and nutrition.
Some people with ALS have problems with memory and decision-making, and some are eventually diagnosed with a form of dementia called frontotemporal dementia.
Amyotrophic lateral sclerosis is difficult to diagnose early because it can mimic other neurological diseases. Tests to rule out other conditions might include:
- Electromyogram (EMG).
- Nerve conduction study.
- MRI. Using radio waves and a powerful magnetic field, an MRI produces detailed images of your brai and spinal cord. An MRI can reveal spinal cord tumors, herniated disks in your neck or other conditions that might be causing your symptoms.
- Blood and urine tests.
- Spinal tap (lumbar puncture). This involves removing a sample of your spinal fluid for laboratory testing using a small needle inserted between two vertebrae in your lower back.
- Muscle biopsy. If your doctor believes you may have a muscle disease rather than ALS, you might undergo a muscle biopsy.
Treatments can't reverse the damage of amyotrophic lateral sclerosis, but they can slow the progression of symptoms, prevent complications, and make you more comfortable and independent. You might need an integrated team of doctors trained in many areas and other health care professionals to provide your care. This might prolong your survival and improve your quality of life. Our team will help you select the right treatments for you.
The Food and Drug Administration has approved two drugs for treating ALS:
- Riluzole (Rilutek). Taken orally, this drug has been shown to increase life expectancy by three to six months. It can cause side effects such as dizziness, gastrointestinal conditions and liver function changes. Your doctor will monitor your blood counts and liver functions while you're on the drug.
- Edaravone (Radicava). This drug, given by intravenous infusion, has been shown to reduce the decline in daily functioning. Its effect on life span isn't yet known. Side effects can include bruising, headache and shortness of breath. This medication is given daily for two weeks a month.
Your doctor might also prescribe medications to provide relief from other symptoms, including:
- Muscle cramps and spasms
- Excessive saliva and phlegm
- Sleep problems
- Uncontrolled outbursts of laughing or crying
- Breathing care.
- Physical therapy. A physical therapist can address pain, walking, mobility, bracing and equipment needs that help you stay independent. Practicing low-impact exercises can help maintain your cardiovascular fitness, muscle strength and range of motion for as long as possible.
- Regular exercise can also help improve your sense of well-being.
- Occupational therapy. An occupational therapist can help you find ways to remain independent despite hand and arm weakness.
- Speech therapy. A speech therapist can teach you adaptive techniques to make your speech more understandable.
- Nutritional support.
- Psychological and social support.
Potential future treatments
Clinical studies on promising medications and treatments are occurring for ALS all the time.